Unsure about cause of browning avocado leaves

Question

My avocado leaves are all looking like this and dying (3 years old plant). I gave it some fertilizers a while ago, like 2-3 months. I am sure I am not watering too much, been doing rarely since the winter, once a week or even less. I hope you can help me save it!

Answer 1

One possibility is salt burn, although that tends to brown more from the tip of the leaf like the one on the right, not all over like the leaf on the left.

Avocados are very sensitive to salt: even the amount of salt in tap water from the Colorado River can be too much, especially with frequent light watering where water can evaporate.

For larger outdoor plants, gypsum and a couple of deep waterings to leech salts out the bottom every year or 2 are the general fixes plants. Also, outdoor avocados do much much better with deep mulch covering the soil, both reducing evaporation that leaves salt behind, and keeping the very shallow roots cool.

My guess is that your pot is too small for the size of your plant, so you're watering frequently and over a year or so salts have built up. While avocados are sensitive to transplanting or repotting, I would try to repot that in something twice the diameter, keeping the current soil ball as intact as possible, and perhaps switch to watering with reverse osmosis water if you have that in your house.